Polyamide resins are excellent in terms of tensile strength and impact strength, and are in extensive use as a material for packaging films for foods or the like. For example, a film of a resin composition comprising a polyamide resin containing a hydrophilic compound incorporated thereinto has been proposed as a film having water vapor permeability which is for packaging water-containing foods and thereafter heating and drying the packaged foods to diminish or remove the water contained therein (see, for example, Patent Document 1).
However, films formed from the resin composition disclosed in Patent Document 1 have a practically insufficient water vapor transmission rate (hereinafter referred to as WVTR), and there is a possibility that drying of the packaged contents might require a prolonged time period, resulting in a deterioration of the contents.
Meanwhile, such films are required to have a low elastic modulus, and resin compositions to be used for producing such films are required to be capable of being stably molded by inflation molding, i.e., to have excellent inflation moldability.